Preferred Basis solution in MWI

[mieral]

For the difficulty of getting a preferred basis in the unitary only MWI. I saw this message by Fredrik:

"If we just let it go, it seems very natural to me to (if we insist on trying to interpret QM as a description of the universe) postulate something like "every 1-dimensional subspace of the Hilbert space of the universe represents a world". This eliminates the preferred basis problem."

https://www.physicsforums.com/threads/the-many-worlds-interpretation-of-qm.676537/page-5

What is your objection to Fredrik solution that "every 1-dimensional subspace of the Hilbert space of the universe represents a world"?

 

[Demystifier]

My objection is that we never observe such 1-dimensional worlds. If the point is to explain our observations, then such an interpretation doesn't help.

 

[mieral]

My objection is that we never observe such 1-dimensional worlds. If the point is to explain our observations, then such an interpretation doesn't help.

Does 1-dimensional world mean a basis orthogonal to each other? can you please use other words for it that I can look up?

He who calls himself Fredrik (science adviser) was last seen in Dec 24, 2016. Is he still in our branch/world? Hope he is ok.